Pressure foot for sewing a coil-type zipper stringer



United States Patent [72] Inventors Joseph J. Dolney Denville; Ludwig J. Kuhar, Clark, NJ. [21] App]. No. 827,866 [22] Filed May 26, 1969 [45] Patented Dec. 15, 1970 [73] Assignee The Singer Company New York, N.Y. a corporation of New Jersey [54} PRESSURE FOOT FOR SEWING A COIL-TYPE ZIPPER STRINGER 7 Claims, 4 Drawing Figs.

[52] U.S.Cl 112/151,

112/235, 112/153 [51 Int. Cl D051) 35/00,

DOSb 29/00 {50] Field oi'Seareh 112/151, 152, 153,235,105

[56] References Cited UNlTED STATES PATENTS 2,434,158 H1948 Herr 112/235X 2,581,603 l/1952 Rockerath 112/235 2,857,866 Ill/i958 Porepp 3.003.444 10/1961 Gary Primary Examiner-11. Hampton Hunter Altorneys-Marshall J. Breen, Chester A. Williams, Jr. and

Robert E. Smith 112/153X ll2/l35 ABSTRACT: A presser foot is disclosed for sewing a coil-type zipper stringer using a family-type zigzag sewing machine. An aperture in the presser foot guides a zipper coil under the presser foot to one side of the center needle position, while a portion of the presser foot guides an edge of a material under or to the other side of the center needle position adjacent to the zipper coil so that the zigzag stitching will lock the zipper coil and material together to form a zipper stringer. A second aperture is provided in the presser foot to guide a stuffer cord in parallel contact with the zipper coil to the center needle position under the presser foot but above the material so that PATENT ED om SI97B 7 INVEN'I'URS Joseph Do/ney Ludwig J. Kuhar BY ATTORNEY WIT'NEISS W k BACKGROUND or THE INVENTION Many different methods have been proposed heretofore for securing the fastener elements of a zipper to a tape or fabric.

In the manufacture of zippers of the type including metal or plastic teeth, the usual procedure includes the step of sewing a stuffer cord to the edge of the tape (or fabric)or folding the cord in a portion of the tape (or fabric) and stitching through the cord and tape (or fabric) to secure them using a standard presser foot. The tape (or fabric) with the stuffer cord thereon is then fed into a machine in which the fastener teeth are made and/or cramped or clinched on the cordjand a portion of the. tape (or fabric).

In the manufacture of the so-called spiral or coil type of fastener, the best practice has been to use a special type of tape which is woven in such a manner that picks are dropped between the edges of the tape to give a ladderlike formation through which the coil strip is slipped to secure it in position. The tape is then sewn to a fabric'in the; usual manner. Attempts have been made to sew the coiled strip directly to the tape using straight stitching but have not-proved to be very successful because the convolutions of the strip stretch and contract so that spacing of the convolutions may not be exact. As a result, the straight stitch sewing machine needle may not enter between each convolution and make a secure tie with the tape. Moreover, the needle may actually strike the coiled strip and break either the strip or the needle.

SUMMARY OF THE INVENTION This invention relates to a ipresser foot on a zigzag sewing machine, particularly of the family type, for sewing a coil-type zipper stringer of a slide fastener in one operation and of any desired length. The presser foot guides and positions a zipper coil of any desired length under the presser foot adjacent to an edge of the material so that the zigzag stitching will lock'the zipper coil and material together'to form a zipper stringer. The presser foot also provides for a stuffer cord of any desired length to be guided in parallel contact with the zipper coil to form the zipper stringer. The toe of the presser foot remains in contact with the bed slide of the sewing machine during the entire feeding cycle to aid in the positioning of the material.

One object of the invention is to provide a presser foot of the above character wherein the number of steps necessary to sew a zipper to a fabric of an article or garment is reduced. The tape, to which the fastener elements are usually secured, is eliminated and therefore no basting operation is necessary to position the tape on the fabric. The elimination of the tape reduces the bulk and shadowed seam appearance. Also the home sewer is no longer restricted by standard zipper availability as to lengths, colors and textures, since the fabric stringer now is composed of the actual panel of the material of the garment. The home sewer can purchase the zipper coil and the stuffer cord in great lengths, and with the aid of the present invention, the home sewer can attach the coil and,

cord directly to the garment fabric. Thus, for example, the

present invention pennits the home sewer to readilyproduce a dress style having a zipper extending from the hem of the dress to the neck where the fabric of the dress functions as a part of the stringer.

Another object of this invention is to provide a presser foot which permits the left and. right zipper coil to be applied separately, allowing the sewer to stitch on a single garment part thereby reducing the amount of manipulating of the garment which takes place at the sewing machine.

Still another object of this invention is to provide a simple and efficient presser foot which would be readily attached to the presser bar of a family-type zigzag sewing machine, and which would effectually permit curved, spherical and angled seam designs. 1

BRIEF DESCRIPTION OF THE DRAWINGS Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it, when read in conjunction with the accompanying drawings in which:

FIG. 1 represents a fragmentary perspective view taken in the needle region of a zigzag sewing machine, such view showing a presser foot according to the present invention in an operative position for sewing a coil-type zipper stringer;

FIG. 2 represents a front elevational view of a sole plate of the presser foot of this invention as illustrated in FIG. 1, showing the guide apertures for both the zipper coil and the stuffer cord;

FIG. 3 represents a side elevational view of the sole plate of this invention, showing the angled down toe of the presser foot; and g FIG. 4 represents a rear elevational view of the sole plate of this invention, showing the clearance groove for the passage of the sew zipper stringer.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 illustrates a fragment of a bracket arm 11 of a zigzag sewing machine frame including a presser bar bushing 12 secured in the bracket arm 11 and a presser bar 13 endwise slideable in the, bushing 12. The presser bar 13, as is conventional, may be biased downwardly by a spring (not shown) and furthermore, the presser bar 13 may be raised at will by the sewing machine operator by means of a presser-lifting lever (not shown) carried on the bracket arm 11. Also endwise reciprocable in the bracket arm 11 is a needle bar 14 carrying a needle 15 which holds a thread T for the formation of stitches. The sewing machine frame includes a work supporting bed 16 beneath the bracket arm 11. Carried on the bed 16 are a bed slide 17 and a throat plate 18 which is formed with slots (not shown) through which a feed dog (not shown) of a conventional zigzag sewing machine feed mechanism is operative. Carried on the presser bar 13 and urged. downwardly against the bed slide 17 and the throat plate 18 is the presser foot 20 of this invention.

.The'presser foot 20 comprises a shank 21 adaptable for connection to the presser bar 13, and a sole plate 22 which may be exchangeably accommodated on the shank 21. The sole plate 22 is formed with upstanding ears 23 spaced apart a distance substantially equal to the thickness of the presser foot shank 21. Carried by the cars 23 and extending transversely therebetween is a cylindrical pivot pin 24- The presser foot shank 21 is formed at thetop with a presser bar-accommodating seat and is secured to the presser bar 13 by means of a shouldered clamp screw 25 which is threaded into the presser bar 13. Depending from the presser bar-accommodating seat is a blade having a narrow elongated slot 26 extending substantially lengthwise of the presser foot shank blade. The slot 26 joins a downwardly open socket (not shown) formed in the bottom of the blade into which the cylindrical pivot pin 24 of the presser foot plate 22 may be accommodated. When a force abnormally higher than that encountered during sewing is applied downwardly on the presser foot sole plate 22, the sole plate 22 will be released from the presser foot shank 21 and a different presser foot sole plate may be substituted therefor. The above and further details of the structure of the presser foot shank 21, showing the relationship of the shank 21 to the presser bar 13 and to a presser foot sole plate, are set forth in a copending application, Snap- On Presser Foot Shank, Ser. No. 752,663, filed Aug. 14, 1968, now U.S. Pat. No. 3,489,l l4, assigned to the assignee of this invention.

A needle-receiving aperture 31 extends vertically through the sole plate 22, such aperture 31 being formed to permit zigzag stitching. A slot 32 extends from the needle aperture 31 to arr ledge of the sole plate 22 to allow the thread T to pass therethrough when a material or a fabric F is desired to be removed from or returned under the presser foot 20 during the sewing of the zipper stringer Z. A raised front portion 33 of the sole plate 22 is angled upwardly from the aperture 31. Two parallel guide apertures 34, 35 are formed in portion 33. The apertures 34, 35 appear as holes or openings in the front edge of portion 33, as illustrated in FIG. 2, and extend in open communication with each other along their lengths through portion 33 into communication with the needle aperture 31, as shown in FIG. 3. Guide aperture 34 is in line with the center position of the needle and acts to guide a stuffer cord S through portion 33 to align the stuffer cord S at the center needle position under the presser foot 20. The other aperture 35, usually the larger of the two, guides a zipper coil C through portion 33 in parallel contact with the stuffer cord S so that the zipper coil C and the stuffer cord S are positioned side by side within portion 33 and under the presser foot at the needle aperture 31. The guide apertures 34, 35 are able to receive a stuffer cord and a zipper coil, respectively, of any desired length, thus permitting an extremely long zipper stringer to be made directly on a fabric.

A toe portion 36 has been angled downwardly from the needle aperture 31 to the forward edge of the sole plate 22, as best shown in FIG. 3 whereby toe portion 36 pivots about the axis of pin 24, so that the toe of the presser foot 20 remains in contact with the bed slide 17 during the entire feeding cycle. Portion 37 connects the raised front portion 33 to toe portion 36..A vertical side surface 38 of the sole plate 22 extending downwardly from portion 33, along a wall of portion 37 and an edge of portion 36 to the bottom surface of portion 36 acts to guide an edge of the material of the fabric F under the needle aperture 31. The surface 38, as shown in FIG. 2 is substantially in line with the stuffer cord aperture'34, and therefore also substantially in line with the center needle position. The edge of the fabric F may be approximately aligned with the center needle position or slightly to the left of the center needleposition, with the bulk of the material of the fabric F to the left thereof, as shown in FIG. 1. At the needle aperture 31, the fabric F is positioned under the stuffer cord S in contact relationship therewith under the presser foot 20, wherein the fabric F is maintained on one side (the left side) of the stuffer cord S and the zipper coil C is maintained on the other side (the right side). Obviously, the sole plate 22 of the presser foot 20 could be constructed so the relative positions of the zipper coil C and the fabric F are reversed.

Adjustment is made with the stitch width selector (not shown) of the sewing machine such that the total throw of the needle 15 during one stitch sequence encompasses from the fabric F on one side of the stuffer cord S to an inside portion of a' loop of the zipper coil C on the other side of the stuffer cord. With the tension on the thread T adjusted to give an unbalanced stitch, the stitching will lock together the fabric F, thestuffer cord S and the zipper coil C with the stitch crossover occurring adjacent to a bottom portion of the stuffer cord S to form the zipper stringer Z.

f If desired, a portion of the zipper coil aperture 35 adjacent to the needle aperture 31 could be made slightly smaller than the. zipper coil C to exert a slight frictional force on the next loop to be sewn causing the spacing between the loop being sewn and the next loop to be made larger, and thereby increasing the clearance for the needle 15. Obviously, the above frictional force is substantially less than the force exerted by the feed dog of the sewing machine, which is used to move the fabric F and the sewn zipper stringer Z, and also to draw the stuffer cord S and the zipper coil C through the guide apertu'res 34, 35 respectively, to their sew .positions under the sole plate 22 at the needle aperture 31.

.The above and further details of the structure of the zipper stringer Z are setforth in a copending application, Coil-Type Zipper Stringer and Method of Making the Stringer, Ser. No. 833,972, filed Jun. 17, I969, assigned to the assignee of this invention.

A clearance groove 39 is formed in the bottom surface of the sole plate 22 extending from the needle aperture 31, through the rear portion 40 to the rear edge of the sole plate 22, as shown in FIG. 3, to allow passage of the sewn zipper stringer Z. The groove 39 is stepped, as shown in FIG. 4, to provide for the difference in thickness between the sewn zipper coil C and the sewn stuffer cord S, where the sewn zipper coil C is usually the thicker of the two. The rear portion 40 is turned up in the conventional manner.

Though the presser foot shank 21 is for best results preferably fabricated of a sheet metal stamping using a selected type of steel, the presser foot sole plate 2 of this invention is preferably fabricated of a plastic material, which may be either transparent or opaque.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of the invention which is for purposes of illustration only and not to be construed as a limitation of the invention.

We claim:

1. A presser foot for use with a zigzag sewing machine having a needle capable of movement to either side of a center needle position, said presser foot comprising a sole plate having a needle-receiving aperture extending vertically therethrough, a front portion of said sole plate being adjacent to said needle-receiving aperture and having first guide means formed therein communicating with said needle-receiving aperture to position a zipper coil under said sole plate to one side of the center needle position at said needle-receiving aperture, and second guide means adjacent to said front portion to guide an edge of a material under said sole plate to approximately the center needle position at the needle-receiving aperture with the bulk of the material being positioned to the other side of the center needle position so that the zipper coil and the material are in sewing position at the needle-receiving aperture for making a coil-type zipper stringer.

2. A presser foot according to claim 1 wherein said front portion of said sole plate is angled upwardly from said needlereceiving aperture to a front edge of said front portion, said first guide means being a guide aperture formed in said front edge and extending downwardly through said front portion into communication with said needle-receiving aperture, said second guide means being a vertical surface of said sole plate spaced to one side of said guide aperture and extending downwardly from said front portion between said front edge and said needle-receiving aperture, and said vertical surface being substantially in line with the center needle position.

3. A presser foot according to claim 1 wherein a toe portion of said sole plate is angled downwardly from the needlereceiving aperture to a forward edge of said sole plate, whereby the toe portion remains in contact with the sewing machine during an entire feeding cycle.

4. A presser foot according to claim 1 wherein a rear portion of said sole plate adjacent to said needle-receiving aperture has a clearance groove formed therein extending from said needle-receiving aperture to a rear edge of said sole plate, whereby said clearance groove allows for passage of the sewn zipper stringer.

5. A presser foot according to claim 1 wherein said sole plate has a third guide means formed in said front portion communicating with said needle-receiving aperture and said first guide means to position a stuffer cord under said sole plate in alignment with the center needle position at said needle-receiving aperture so that the stuffer cord is in parallel contact with the zipper coil, whereby zigzag stitching will be able to lock the zipper coil, the material and the stuffer cord together to form the zipper stringer.

6. A presser foot according to claim 5 wherein said front portion of said sole plate is angled upwardly from said needlereceiving aperture to a front edge of said front portion, said first and third guide means being a coil aperture and a cord aperture, respectively, formed in said front edge and extending, parallel to each other and in open communication with each other along their lengths; downwardly through said front is portion into communication with said needle-receiving aper- .spaced to one side of said coil aperture and being positioned LII below and substantially in line with said cord aperture, said vertical surface extending downwardly from said front portion between said front edge and said needle-receiving aperture, whereby the material is positioned to one side of the zipper coil and under the stuffer cord at the needle-receiving aperture. 

